A Lesson in Scope Change

Dec 25, 2024

I've recently purchased a Flipper Zero as cheap tool to test/play around with sub-ghz wireless and also as a remote UART console when dealing with door units for ManageMemberships. You can also emulate NFC cards, including Tonies. My son has a Tonie box and after observing the emulation I learned about a larger group of people hacking their tonies. Combined with my recent purchase of a 3D printer, I was thinking it should be no problem to create my own tonies.

Printing the new figurines was easy enough:

Unfortunately, it turned out that Tonies use an 8bit UID NFC. Writing these seemed to be a bit of a PITA. I could have emulated it like my Flipper but that would require batteries directly on the figures.

So I broke down and decided to 3d print an enclosure and use some spare electronics I had lying around. Thankfully chatgpt turned me on to the idea of using a MIDI to Arduino converter. So I found some appropriate MIDI files and converted those to Arduino functions that would pulse piezo speakers. The circuit looked like the following:

And here is an earlier revision of it on a breadboard:

The final product didn't turn out as well as I would have liked it nor did it end as badly as it would have if I just gave up when the Tonie NFC issue stopped me. A video of the final product can be found here